David R Bell1, Stephanie M Kulow2, Mikel R Stiffler2, Mason D Smith2. 1. Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Wisconsin Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Wisconsin drbell2@wisc.edu. 2. Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin Wisconsin Injury in Sport Laboratory, University of Wisconsin-Madison, Wisconsin.
Abstract
BACKGROUND: Single-legged squat mechanics change after anterior cruciate ligament (ACL) reconstruction and rehabilitation, but it is unclear if changes in squat mechanics are graft specific. PURPOSE: To investigate graft differences in biomechanics of the knee, hip, and trunk during the single-legged squat in patients with ACL-reconstructed knees, determine if these factors were associated with deficits in knee extension moment, and determine if subjective knee function and squat biomechanics are related. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 106 individuals were grouped based on surgical status and graft type (51 control, 34 bone-patellar tendon-bone [BPTB], 21 ipsilateral semitendinosus and gracilis autograft [ISGA]). Motion capture interfaced with force plates was used to capture single-legged squat performance in the ACL reconstructed and dominant control limbs. Variables were captured at peak knee flexion. RESULTS: Controls exhibited greater knee extension moment (P = .04), knee flexion (P = .002), and hip adduction angles (P = .04) compared with the reconstructed groups. The ISGA group demonstrated greater forward (P = .01) and lateral (P = .002) trunk flexion over the reconstructed limb. Summated extension moment did not differ between groups (P = .42). Knee extension moment was correlated with lateral trunk flexion (r = -0.31, P = .03) in the control group and knee flexion angle (r = -0.44, P = .04) in the ISGA group. Subjective knee function scores were correlated with lateral trunk flexion (r = -0.45, P = .008) in the BPTB group and with hip adduction angle (r = -0.46, P = .04) and hip extension moment (r = 0.48, P = .03) in the ISGA group. CONCLUSION: Knee and hip biomechanics were related to surgical status but not graft type. Increased forward and lateral trunk motion in the ISGA group may be a mechanism to protect the knee by minimizing motion during squatting or related to surgical selection bias. Secondary findings (summated extensor moments and correlations) most likely represent a strategy to shift the squat demands from the knee to the hip. CLINICAL RELEVANCE: Clinicians should target these neuromuscular deficits during rehabilitation and training programs after ACL reconstruction.
BACKGROUND: Single-legged squat mechanics change after anterior cruciate ligament (ACL) reconstruction and rehabilitation, but it is unclear if changes in squat mechanics are graft specific. PURPOSE: To investigate graft differences in biomechanics of the knee, hip, and trunk during the single-legged squat in patients with ACL-reconstructed knees, determine if these factors were associated with deficits in knee extension moment, and determine if subjective knee function and squat biomechanics are related. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 106 individuals were grouped based on surgical status and graft type (51 control, 34 bone-patellar tendon-bone [BPTB], 21 ipsilateral semitendinosus and gracilis autograft [ISGA]). Motion capture interfaced with force plates was used to capture single-legged squat performance in the ACL reconstructed and dominant control limbs. Variables were captured at peak knee flexion. RESULTS: Controls exhibited greater knee extension moment (P = .04), knee flexion (P = .002), and hip adduction angles (P = .04) compared with the reconstructed groups. The ISGA group demonstrated greater forward (P = .01) and lateral (P = .002) trunk flexion over the reconstructed limb. Summated extension moment did not differ between groups (P = .42). Knee extension moment was correlated with lateral trunk flexion (r = -0.31, P = .03) in the control group and knee flexion angle (r = -0.44, P = .04) in the ISGA group. Subjective knee function scores were correlated with lateral trunk flexion (r = -0.45, P = .008) in the BPTB group and with hip adduction angle (r = -0.46, P = .04) and hip extension moment (r = 0.48, P = .03) in the ISGA group. CONCLUSION: Knee and hip biomechanics were related to surgical status but not graft type. Increased forward and lateral trunk motion in the ISGA group may be a mechanism to protect the knee by minimizing motion during squatting or related to surgical selection bias. Secondary findings (summated extensor moments and correlations) most likely represent a strategy to shift the squat demands from the knee to the hip. CLINICAL RELEVANCE: Clinicians should target these neuromuscular deficits during rehabilitation and training programs after ACL reconstruction.
Authors: David R Bell; Karin A Pfeiffer; Lisa A Cadmus-Bertram; Stephanie M Trigsted; Adam Kelly; Eric G Post; Joseph M Hart; Dane B Cook; Warren R Dunn; Christopher Kuenze Journal: Am J Sports Med Date: 2017-04-18 Impact factor: 6.202
Authors: J Craig Garrison; Joseph Hannon; Shiho Goto; Victor Kosmopoulos; Subhash Aryal; Curtis Bush; James M Bothwell; Steven B Singleton Journal: Orthop J Sports Med Date: 2019-10-04